Refactor color space attribute processing.

getColorSpaceAttribute and stripAttributes have closely related purpose.
Merge them into a single processAttribute function.

This also adjusts which color space attributes are passed to the driver,
based on the EGL extension specifications.

Bug: 78247539
Test: cts-tradefed run singleCommand cts-dev -m CtsDeqpTestCases \
--module-arg CtsDeqpTestCases:include-filter:dEQP-EGL.functional.* \
--skip-preconditions

Change-Id: I79650e0066e54ae92033b280d75f17b4060114bd